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Suppression of wheat-seedling diseases caused by Fusarium culmorum and Microdochium nivale using bacterial seed treatment 总被引：1，自引：0，他引：1
Snow mould, caused by Microdochium nivale , and seedling blight caused by members of the Fusarium complex, are cereal diseases of great economic importance in many temperate zones. In a glasshouse bioassay designed to enhance disease, about 600 plant-associated bacterial isolates obtained by different methods were screened for suppressive effects in wheat against infection caused by Fusarium culmorum . Although most of the isolates tested had a neutral effect on test plants and disease development, a few were synergistic to the pathogen and about one-fifth showed > 80% disease suppression. During five consecutive growing seasons, 164 bacterial isolates were tested in field experiments against both F. culmorum and M. nivale as causal agents of seedling blight. Tests for effects on yield in experiments with spring and winter wheat, performed in different climatic regions of Sweden, showed that disease-suppressive effects were repeatable. The most efficient isolates, three fluorescent pseudomonads and a species of Pantoea , suppressed disease equal to that of the fungicide guazatine, both with respect to crop stand and yield. Seed treatment with Pantoea sp. (isolate MF 626) increased yield by an average of more than 500 kg ha−1 in six field experiments. 相似文献
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Xanthomonas campestris is a seedborne bacterium that causes black rot of crucifers. Substantial crop losses may result from the rapid spread of the bacteria under favourable conditions, especially those occurring during seedling production. A PCR-based method has been developed for the rapid and sensitive detection of the pathovars of X. campestris that affect crucifers. Primers were designed to specifically amplify a 619 bp fragment of the hrpF gene from X. campestris . Amplification products were not detected from other Xanthomonas species, or from other pathogenic or epiphytic bacteria occurring on these plants. To avoid false-negative results arising from the presence of amplification inhibitors in plant extracts, primers targeting a 360 bp section of the internal transcribed spacer (ITS) region from Brassica spp. were included in a multiplex PCR. The assay readily detected X. campestris pv. campestris infections in diseased plants and from bacterial colonies isolated on growth media, and was more sensitive and specific than traditional plating methods and a commercially available ELISA. A seed-washing protocol was optimized to allow the detection of a single artificially infected seed among 10 000 healthy seeds using the multiplex PCR. 相似文献
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Fusarium moniliforme is a widespread facultative endophyte, primarily associated with corn, where it causes extensive crop damage.F. moniliforme can be toxigenic, the carcinogenic fumonisins being accumulated predominantly when the fungus colonizes corn plants. The
pathogen is transmitted both through contaminated seeds and through environmental inoculum. This study utilized markednit-mutantF. moniliforme inoculum in order to evaluate the quantitative significance of seedborne disease transmission. Greenhouse and field trials
demonstrated that seedborne isolates were responsible for up to 50% ofF. moniliforme disease. Seed treatment with the fungicide prochloraz was found to control seedborne transmission and to protect againstF. moniliforme seedling blight. The elimination of seedborne inoculum resulted in reduced incidence of kernel rot and avoided the increment
in soil inoculum accumulation associated with the introduction of infected seeds.
http://www.phytoparasitica.org posting July 10, 2003. 相似文献
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D. C. Rennie V. P. Manolii T. Cao S. F. Hwang R. J. Howard S. E. Strelkov 《Plant pathology》2011,60(5):811-819
Using quantitative PCR, DNA of Plasmodiophora brassicae, the causal agent of clubroot, was detected and quantified on canola, pea and wheat seeds, as well as on potato tubers, all harvested from clubroot‐infested fields in Alberta, Canada. Quantifiable levels of infestation were found on seven of the 46 samples analysed, and ranged from <1·0 × 103 to 3·4 × 104 resting spores per 10 g seeds; the vast majority (80–100%) of resting spores on these samples were viable, as determined by Evan’s blue vital staining. However, the levels of infestation found were generally lower than that required to cause consistent clubroot symptoms in greenhouse plant bioassays. While the occurrence of P. brassicae resting spores on seeds and tubers harvested from clubroot‐infested fields suggests that seedborne dissemination of this pathogen is possible, practices such as commercial seed cleaning may be sufficient to effectively mitigate this risk. 相似文献
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Management of bakanae and bacterial seedling blight diseases in nurseries by irradiating rice seeds with atmospheric plasma 
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下载免费PDF全文 A. Ochi H. Konishi S. Ando K. Sato K. Yokoyama S. Tsushima S. Yoshida T. Morikawa T. Kaneko H. Takahashi 《Plant pathology》2017,66(1):67-76
The control of seedborne rice seedling diseases in the seed beds is important to avoid epidemics in rice nurseries and paddies, which may result in severe yield loss. Recently, irradiation with plasma containing electrons, creating positive or negative ions and neutral species, has been shown to have an antimicrobial effect, probably via generation of reactive oxygen species. This study examines whether two seedborne rice seedling diseases, bakanae disease caused by the fungal pathogen Fusarium fujikuroi, and bacterial seedling blight caused by Burkholderia plantarii, are suppressed by irradiation of infected rice seeds with atmospheric plasma. Seed germination and seedling growth were not inhibited in plasma‐treated healthy seeds. When F. fujikuroi‐infected rice seeds were irradiated with plasma after being immersed in sterile distilled water, bakanae disease severity index and the percentage of plants with symptoms were reduced to 18.1% and 7.8% of non‐irradiated control, respectively, depending on the duration of plasma irradiation. The bacterial seedling blight disease index was also reduced by plasma irradiation in vacuum‐inoculated seeds to 38.6% of the non‐irradiated control, and in infected seeds harvested from spray‐inoculated heads of rice plants to 40.1% of the control. Therefore, plasma irradiation seems to be effective in controlling two independent seedborne rice seedling diseases. 相似文献
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西瓜种传尖孢镰刀菌致病性及其粗毒素对种子发芽的影响 总被引：6，自引：1，他引：5
采用浸胚根法和浸根法对京欣一号西瓜种壳分离得到的尖孢镰刀菌(Fusarium oxysporum)进行致病性试验.结果表明:从接种后发病幼苗上分离得到的分离物与最初接种所用的镰刀菌菌落形态和生长速率等性状基本相同,采用相同的引物对rDNA进行PCR扩增获得的核苷酸序列完全相同,说明这二者为同一种菌,从而证明西瓜种子上所携带的尖孢镰刀菌具有致病性,在国内首次报道了西瓜种传尖孢镰刀菌具有致病性.西瓜种传尖孢镰刀菌培养滤液和粗毒素提取物处理西瓜种子后,种子的发芽势、发芽率和发芽指数均显著降低,其中发芽势下降了16.7%～29.0%,发芽率下降了14.4%～22.3%,发芽指数下降了19.1%～37.1%,说明培养滤液和粗毒素提取物可影响西瓜种子发芽. 相似文献
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甘蓝种传真菌初步研究 总被引：2，自引：1，他引：1
采用洗涤检验法和PDA培养基法对来自北京地区的20个甘蓝品种进行了种传真菌检测和初步鉴定.结果表明,干种子和水洗后种子携带的优势菌群为青霉属(Penicillium spp.)、根霉属(Rhizopus spp.)、曲霉属(Aspergillu,spp.)、链格孢属(Alternaria spp.)真菌,种子洗涤悬浮液中主要检测到曲霉属、链格孢属和青霉属真菌;1%NaClO处理后的甘蓝种子中,除中甘8号种子带茵率达到20.0%外,其余品种的种子带茵率均低于5.0%,携带的真菌主要为曲霉属和链格孢属真菌.此外,还从春甘45和红亩紫甘蓝两个品种的种子上分离到镰刀菌(Fusarium spp.).关于甘蓝种传真菌的研究为国内首次报道. 相似文献
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浙江水稻稻种病原细菌多样性研究 总被引：9，自引：0，他引：9
1997~2000年间对以浙江平原、丘陵及山区为主的稻种病原细菌开展了种类、频率及传病率的研究。从303份稻种样本中分离出3906个菌株,经菌落形态、细菌学、致病性测定后获得201个致病或弱致病菌(占总数的5.15%)。选出致病及非致病代表菌株299个连同23个对照菌株用Biolog进行证实。结果表明种子上所带的病原细菌涉及到6个致病细菌种和5个弱致病种。平原稻区存在较多致病细菌种,山区较少,但两地均以弱致病细菌种占优势;丘陵的强致病细菌种的分离频率显著高于平原与山区。在稻种上携带的11个细菌种中,人工接种和自然感染的病稻种均能引起传病的有Xanthomonas oryzae pv.oryzicola,Pseudomonas fuscovaginae及Acidovorax avenae subsp.avenae. 相似文献
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Xanthomonas axonopodis pv. phaseoli (Xap) is an important seedborne pathogen of Phaseolus vulgaris. Accurate seed health testing methods are critical to protect seed quality and meet phytosanitary requirements. Currently employed selective media‐based methods include several variations in extraction procedures. In order to optimize pathogen extraction from seeds, the influence of different extraction steps on the sensitivity of Xap detection was assessed. Seeds were inoculated by vacuum infiltration with Xap to achieve inoculum levels from 101 to 105 CFU per seed; one contaminated seed was mixed into 1000‐seed subsamples of uncontaminated P. vulgaris seeds. Thirty subsamples of 1000 seeds were tested using each different extraction procedure. These included soaking whole seeds in sterilized saline phosphate buffer, either overnight at 4°C or for 3 h at room temperature, with or without vacuum extraction, and either with or without concentrating the seed extract by centrifuging. Seed extract dilutions were cultured on semiselective agar media MT and XCP1. The percentages of positive subsamples were compared to measure the effects of each extraction step on detection sensitivity. Vacuum extraction and centrifugation of seed extracts increased sensitivity; the highest sensitivity was obtained with the 3 h vacuum extraction followed by centrifugation. These results were confirmed with naturally infested seeds; Xap was detected in 48 of 70 samples using the 3 h vacuum extraction with centrifugation, whereas only 35 of 70 field samples tested positive using overnight soaking, a significant difference. The results suggest that these steps would be valuable modifications to the current method approved by the International Seed Testing Association (ISTA). 相似文献